embryology i - university of minnesotamcloonlab.neuroscience.umn.edu/4100/lectures/n4100 lecture...
Post on 18-Aug-2020
6 Views
Preview:
TRANSCRIPT
Embryology I
Steven McLoon
Department of Neuroscience
University of Minnesota
Nsci4100
Friday (Sept 14) 8:30-9:30am
Surdyk’s Café in Northrop Auditorium
Stop by for a minute or an hour!
2
Coffee Hour
In the blastula stage embryo, the embryonic disk has two layers.
4
During gastrulation, epiblast cells migrate through
the primitive streak to form a three layered embryo.
5
During gastrulation, epiblast cells migrate through
the primitive streak to form a three layered embryo.
6
Factors from the midline mesoderm induce nervous system
in the overlying ectoderm, and the neural plate forms from ectoderm.
7
During neurulation, the neural tube develops from the neural plate.
neural plate neural groove anterior & posterior
neuropores
neural tube
8
During neurulation, the neural tube develops from the neural plate.
9
Incomplete closure of the neural tube is a common birth defect.
Spina bifida:
Incomplete closure of the spinal neural tube and/or the spine.
The severity of the defect is variable and most often is of no consequence.
~1 in 50 live births exhibit spina bifida occulta, making this one of the most common birth defects.
10
Anencephaly = incomplete closure of the brain end of the neural tube
Rare and lethal.
Incomplete closure of the neural tube is a common birth defect.
11
Three swellings at the rostral end of the early neural tube
are the primary brain vesicles.
12
Three swellings at the rostral end of the early neural tube
are the primary brain vesicles.
13
Flexures allow us to stand upright.
14
Flexures allow us to stand upright.
15
Additional changes form the secondary brain vesicles
and optic vesicles.
16
Optic vesicles give rise to neural retina & pigment epithelium.
17
Each major adult brain region develops
from one of the secondary brain vesicles.
18
19
The entire nervous system develops from the neural plate.
20
The telencephalon grows posterior then anterior.
The “ram’s horn” pattern of growth of the telencephalic vesicle creates the temporal lobe.
21
The temporal lobe covers the insula.
The telencephalon grows posterior then anterior.
22
Other adult brain structures exhibit the “ram’s horn” pattern.
The telencephalon grows posterior then anterior.
23
24
The lumen of the neural tube persists
as the ventricular system of the adult brain.
25
The lumen of the neural tube persists
as the ventricular system of the adult brain.
26
Neural Crest
• The neural crest develops from cells at the margin of the neural plate.
27
• Cells delaminate from the dorsal neural tube to form the neural crests.
Neural Crest
28
• Neural crest cells migrate throughout the body and develop into most of
the cells of the peripheral nervous system, as well as other cell types.
Neural Crest
29
neurons - most cranial nerve sensory ganglia - dorsal root ganglia - sympathetic ganglia - parasympathetic ganglia - enteric neurons
glia - schwann cells of nerves - satellite cells of ganglia
neurosecretory cells - thyroid calcitonin (C) cells - adrenal medulla cells
melanocytes some skeletal and connective tissue of head and face muscles
- ciliary muscle of eye - muscle of cranial blood vessels and dermis
mesenchyme of thyroid, parathyroid & salivary glands
• Crest derivatives:
Neural Crest
30
Neural placodes give rise to some neurons
of cranial nerve sensory ganglia.
31
Origin of the Nervous System
top related